To say that someone "can't drink fog" is to say they're a lightweight at drinking.
It's history comes from many a Kerry man who has emerged from a pub after many pints, is suddenly hit by the air and immediately feels more drunk
Chugger is a combination of the words charity and mugger. A charity mugger is a generally a student or young adult (paid) volunteer who aggressively asks you to fill in a questionnaire for their particular cause be it Concern, Greenpeace, Baby Seal Clubbers. Generally chuggers don't take no for an answer so it is better to never make eye contact with them and tell them to feck off if they even open their mouths. In the movie Airplane you can see an example of how to deal with chuggers effectively.
